In conventional magnetic disk devices, when abnormal contact between a magnetic head and a recording medium is detected at the time of setting a control value of a thermal actuator, a trial to detect contact is performed several times at the same radial position on a magnetic disk to make contact until variations of detection results become a certain value or smaller, thereby determining presence or absence of abnormal contact detection.
Meanwhile, contact detection is shifted due to a habit of an algorithm depending on a contact detection method so that it is difficult to eliminate a situation where the contact detection is erroneous although repetitive reproducibility is good. In addition, it is possible to perform control to make a gap between the magnetic head and the recording medium more constant if using a high-order function (polynomial), but it is difficult to accurately determine the abnormal contact detection only with a fitting error obtained by performing fitting using the high-order function when there is abnormal contact between the magnetic head and the recording medium.
An object to be solved by the invention is to provide a control value setting method of a thermal actuator for a magnetic disk device capable of accurately detecting abnormal contact when setting a control value of the thermal actuator for the magnetic disk.